Fact Sheet
What are spiders?
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Spiders have been around for a long time – they evolved around 400
million years ago, well before dinosaurs! They are an important part of
the natural environment because they eat many insects (including pest
insects) and are themselves eaten by other arthropods, birds, reptiles and
mammals. Also, people are working out new uses for spider venom and
silk, including medicines, pesticides and fibres.
Spider morphology
Spiders have a number of interesting features:
cephalothorax
abdomen
pedipalp
chelicerae
spinnerets
jointed leg
Spider life
• Two main body parts (cephalothorax and
abdomen)
• 8 jointed legs (young spiders can re-grow
lost legs - note that spiders’ legs are
attached to their cephalothorax)
• Scopula (brushes of fine hairs on the ends
of their legs that allow them to adhere to
vertical surfaces)
• 6-8 simple lensed eyes (more like human
eyes than insect eyes)
• Chelicerae (appendages with fangs for
tearing or piercing prey)
• Pedipalps (for holding prey and used during
mating)
• Spinnerets (silk spinning organs)
Spiders generally have a large number of young because not many survive to become adults.
They begin life in an egg sac, which they might share with between 4 and 600 siblings. When
they hatch, young spiderlings stay within their sac and grow until they need to shed their skin.
Spiders shed their skins throughout their lives because their skins do not grow as the spider
grows (they typically moult 5 to 10 times during their lives). After their first skin moult, spiderlings
cut holes in the egg sac to get out. After a few days they begin to disperse to find new homes.
Most small spiders live for less than a year, while larger spiders can live for up to 25 years. Male
spiders typically die after mating. In some spider species, females die after they lay eggs, but
for other species the females live to protect their eggs and may breed again in later years.
Spider hunting
Spiders are carnivorous and catch live prey. When they catch their prey, spiders inject venom to
immobilise (and sometimes kill) it. Different spiders use different methods to capture prey:
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Building webs (e.g. orb weavers and red-backs)
Sitting-and-waiting for prey to come to them (e.g. trapdoors)
Chasing prey (e.g. wolf spiders and huntsmen)
Attacking other spiders in their webs (e.g. white-tails)